Greater Melbourne Transit Supply Index (SI) scores for SA1 2021 boundaries

James Reynolds

2024-01-30

Introduction

Monash University’s Public Transport Research Group (PTRG) is commencing a project that will make use of hourly Transit Service Index (SI) scores for Statistical Area Level 1 (SA1) 2021 census boundaries within Greater Melbourne. Code to calculate SI scores from GTFS datasets has recently been developed into an R package. Development of that code is reported separately (see Reynolds (2024Reynolds, James. 2024. “Gtfssupplyindex.” https://github.com/James-Reynolds/gtfssupplyindex.)).

The next step, therefore, is to output the SI scores for Greater Melbourne and check the results. This document describes the calculation of the SI scores for SA1 zones in Greater Melbourne for Tuesday 10th, Saturday 14th and Sunday 15th October, 2023, and reviews the results.

The rest of this document is structured as follows: the next section discusses the research context of the the Supply Index. This is followed by a brief discussion of the methodology. In the fourth section results are presented, including SI scores for SA1s across Greater Melbourne on an hour-by-hour basis. Results are then discussed, followed by a brief conclusion that includes the identification of directions for future research.

Research context

GTFS

The introduction of the General Transit Feed Specification (GTFS) and widespread release of schedule data in this format has helped towards making transit metrics more broadly available and useable. GTFS is an open, text-based format that was developed originally to allow transit information to be included in the Google Maps navigation platform (MobilityData undatedMobilityData. undated. General Transit Feed Specification (GTFS). {https://gtfs.org/}.). The data structure is shown in the below figure.

GTFS entity relationship diagram. Source: adapted by author from Alamri et al (2023) and the GTFS Schedule Reference (16/11/2023 revision).

GTFS entity relationship diagram. Source: adapted by author from Alamri et al (2023) and the GTFS Schedule Reference (16/11/2023 revision).

In the Entity Relationship Diargram (ERD) shown above, each box represents a database table in the GTFS, with table rows indicating the variables (columns) included in each1 For example, each record in the ‘stops’ table includes a value for stop_id, stop_name, stop_lat and stop_lon.. Relationships between the tables are indicated by the connecting lines, and Primary Key (PK) and Foreign Key (FK) designations2 For example, stop_id also appears in the ‘stop_times’ table as a Primary Key and Foreign Key.. “Crow’s feet” indicate the relationships between each table3 See https://i.stack.imgur.com/fxaAq.png for guide to the symbols. But, for example, the stops table is required, with the stop_id field providing a unique (primary) key for every stop. Within the stop_times table (which is also required) the stop_id field is a foreign key. Each unique stop_id can appear many times in the stop_times table, but must appear only once in the stops table. In the stop_times table each combination of trip_id, stop_id and arrival time must be unique (But, see note 2!) meaning that these fields represent a composite key..

The Transit Suppy Index

\[\begin{equation} SI_{area, time} = \sum{\frac{Area_{Bn}}{Area_{area}}*SL_{n, time}} \end{equation}\]

The Transit Supply Index (SI) was developed by Currie and Senbergs (2007Currie, Graham, and Zed Senbergs. 2007. Identifying spatial gaps in public transport provision for socially disadvantaged Australians: the Melbourne needs-gap study.” Australasian Transport Research Forum.). Its equation is shown in the margin4 (1) \(SI_{area, time}\) is the Supply Index for the area of interest and a given period of time; (2) \(Area_{Bn}\) is the buffer area for each stop (n) within the area of interest. In Currie and Senbergs (2007) this was based on a radius of 400 metres for bus and tram stops, and 800 metres for railway stations; (3) \(Area_{area}\) is the area of the area of interest; and (4) \(SL_{n,time}\) is the number of transit arrivals for each stop for a given time period. Minor adjustments have been made to generalise the equation, as Currie and Senbergs (2007) focus was the context of Melbourne’s Census Collection Districts (CCD) and calculations based on a week of transit service. CCDs predate the introduction of Statistical Areas 1, 2, 3, and 4 (SA1, SA2, SA3, SA4), and other geographical divisions currently used by the Australian Bureau of Statistics (ABS), which may be more familiar to readers.

An advantage of the SI is that it is a relatively simple number to calculate, understand and explain. It describes the number of transit arrivals at stops within an area of interest and time frame, multiplied by a factor accounting for the proportion of the area of interest that is within typical walking distance of each stop. Hence, more services, more stops and higher frequencies would all increase the SI score.

Simplicity is also helped by the way that the Index is additive. \(SI_{area, time}\) scores can be aggregated to calculate an overall score across multiple time periods or for a region encompassing multiple areas of interest.

gtfssupplyindex R package

R (R Core Team 2023R Core Team. 2023. R: A Language and Environment for Statistical Computing. Vienna, Austria: R Foundation for Statistical Computing. https://www.R-project.org/.) is a widely used and readily available statistical programming language. This was adopted for development of a package of functions and tools to calculate SI scores from a GTFS dataset. The package development setup and workflow described by Wickham and Bryan (2023Wickham, Hadley, and Jennifer Bryan. 2023. R Packages. " O’Reilly Media, Inc.". https://r-pkgs.org/.) was adopted. The package is available and documented on github (Reynolds 2024Reynolds, James. 2024. “Gtfssupplyindex.” https://github.com/James-Reynolds/gtfssupplyindex.).

The structure and functions used to generate each table are shown in the below Entity Relationship Diagram (ERD).

Entity Relationship Diagram (ERD) showing the data structure and functions of the gtfssupplyindex package

Entity Relationship Diagram (ERD) showing the data structure and functions of the gtfssupplyindex package

The package takes input from three files:

The ultimate goal of the functions included in the gtfssupplyindex package is to output either a si_by_area table (bottom row, second from right) or the si_by_area_and_hour table (bottom right). which reports the SI score for each hour of the day across dates specified by the user.

Included in the package is an example GTFS dataset from the Mornington Penninsula Tourist Railway. The output (si_by_area_and_hour) table is shown as an example below.

Mornington Penninsula Tourist Railway hourly SI values for December 30, 2018, for SA1 zones, first six entries — THIS IS WHAT THE si_by_area_and_hour TABLE LOOKS LIKE

area_id SI hour_starting
214021381 0.0000672 10:00
214021385 0.0000000 10:00
214021591 0.2436873 10:00
214021592 0.0684965 10:00
214021381 0.0522962 11:00
214021385 0.0067970 11:00

Mornington Penninsula Tourist Railway hourly SI values for December 30, 2018, for SA1 zones, by hour — THIS IS A ‘WIDER’ VERSION OF THE si_by_area_and_hour TABLE

area_id 10:00 11:00 12:00 13:00 14:00 15:00
214021381 0.0000672 0.0522962 0.0523635 0.0000672 0.0522962 0.0523635
214021385 0.0000000 0.0067970 0.0067970 0.0000000 0.0067970 0.0067970
214021591 0.2436873 0.1366432 0.3803305 0.1366432 0.2436873 0.3803305
214021592 0.0684965 0.0000000 0.0684965 0.0000000 0.0684965 0.0684965

The upper table shows first six entries in the ‘longer’ version of the table. Each record shows the SI score for a unique combination of area_id5 Here the SA1 2021 zones and hour_starting6 The Mornington Penninsula Railway only runs between 10am and 4pm on the day in question.. The lower table shows the same data, but in a ‘wider’ format so that all hour_starting SI scores a visible7 As the Mornington Penninsula Railway has only 3 stops, only 5 SA1 2021 zones have SI scores.. Further details of the Mornington Penninsula Railway calculations8 Including hand verification. are available in the package documentation on github(Reynolds 2024Reynolds, James. 2024. “Gtfssupplyindex.” https://github.com/James-Reynolds/gtfssupplyindex.).

Methodology

In this document hourly SI scores are reported for all SA1 2021 zones within Greater Melbourne. Scores are calculated for Tuesday 10th, Saturday 14th and Sunday 15th October, 2023. These datas are selected so as to match the typical census timing of a Tuesday early in October, although 2023 is not actually a census year.

GTFS data was obtained from Transit Mobility Data, (2023Transit Mobility Data,. 2023. “PTV GTFS - OpenMobilityData.” 2023. https://transitfeeds.com/p/ptv/497.), with the October 6, 2023 dataset selected. Some minor adjustments were made to this dataset to remove duplicate stop_ids from the stops.txt file.

Hourly SI scores were obtained for all modes across all of Greater Melbourne.

Victorian GTFS and SA1 zones within the Greater Melbourne GCCSA, hourly SI values for October 10, 2023, first 6 SA1 zones, 4am to 11pm only

area_id 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00
20601110601 0 10 27 45 51 51 43 39 38 43 38 47 51 51 51 32 23 18 8 5
20601110605 2 20 86 99 93 85 73 69 65 67 75 88 103 100 86 65 44 38 29 27
20601110606 1 19 69 84 84 73 68 62 60 61 67 75 90 85 70 56 35 29 19 18
20601110608 0 11 24 36 39 36 32 29 29 30 30 34 39 38 33 25 17 13 9 8
20601110609 2 26 64 90 90 89 74 69 66 69 72 82 97 97 85 68 50 41 29 25
20601110610 4 40 99 137 131 133 108 102 95 99 106 121 146 150 130 107 82 66 50 43

SI scores were also obtained for each mode separately.

Victorian GTFS and SA1 zones within the Greater Melbourne GCCSA, hourly SI values for October 10, 2023, tram only, first 6 SA1 zones, 4am to 11pm only

area_id 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00 25:00
20601110601 10 13 16 16 14 13 12 13 12 14 15 15 16 14 8 6 5 5 3 0
20601110605 54 68 63 64 51 49 44 47 52 60 70 73 65 49 37 31 29 27 18 4
20601110606 34 48 49 48 40 38 36 37 41 44 50 53 46 36 26 21 19 18 12 2
20601110608 12 22 25 24 21 19 19 19 20 22 23 24 22 17 12 9 8 8 5 0
20601110609 47 66 62 63 52 49 46 48 51 58 68 70 62 49 36 29 26 25 16 3
20601110610 85 116 102 105 87 81 73 78 85 96 117 121 105 85 64 51 47 43 29 7

Victorian GTFS and SA1 zones within the Greater Melbourne GCCSA, hourly SI values for October 10, 2023, rail only, first 6 SA1 zones, 4am to 11pm only

area_id 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00 25:00 26:00
20601110608 1 1 1 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0
20601110712 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0
20601110716 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0
20601110720 4 4 4 3 3 3 3 3 3 4 3 4 3 3 2 2 2 2 0 0
20601110721 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
20601110912 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Victorian GTFS and SA1 zones within the Greater Melbourne GCCSA, hourly SI values for October 10, 2023, bus only, first 6 SA1 zones, 4am to 11pm only

area_id 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00
20601110601 0 3 17 32 35 35 29 26 26 30 26 33 35 35 35 19 15 12 3 0
20601110605 0 0 32 31 30 21 22 20 20 20 23 28 33 27 20 17 7 7 0 0
20601110606 0 0 35 36 35 25 28 24 24 24 26 32 39 32 24 20 8 8 0 0
20601110608 0 1 11 13 14 11 11 10 10 10 10 12 15 13 11 8 5 4 1 0
20601110609 0 3 17 24 28 26 21 20 20 21 21 25 29 27 23 19 14 12 2 0
20601110610 0 4 14 22 28 28 21 21 21 21 21 24 29 28 25 21 18 14 3 0

Results

Results are saved in a csv file format together with the other documentation of this project9 See https://github.com/James-Reynolds/gtfssupplyindex_greater_melbourne_SA12021_hourly

These files contain a large amount of data, as there are a lot of SA1 zones within Greater Melbourne. Hence, only selected results are presented in the following sections to demonstrate the calculated scores.

All modes

Lang Lang

Lang Lang is a small township in the south-east of the Greater Melbourne area, on the way to Phillip Island. The SA1 zone boundaries in the vicinity of the township are shown in the below figure.

SA1 zone boundaries in Lang Lang

SA1 zone boundaries in Lang Lang
SI score results for SA1 21201154812 are shown in the following tables:

Victorian GTFS and Lang Lang SA1 zone 21201154812, hourly SI values for October 10, 2023, 6am to 11pm only

area_id 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00
21201154812 1.78 3.56 1.78 0 1.78 1.78 1.78 1.78 1.78 1.78 1.78 1.78 1.78 1.78 1.78 0 1.78 0

Victorian GTFS and Lang Lang SA1 zone 21201154812, hourly SI values for October 14, 2023, 6am to 11pm only

area_id 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00
21201154812 0 0 1.78 0 1.78 0 3.56 0 0 1.78 1.78 0 1.78 1.78 0 0 0 0

Victorian GTFS and Lang Lang SA1 zone 21201154812, hourly SI values for October 15, 2023, 6am to 11pm only

area_id 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00
21201154812 0 0 1.78 0 1.78 0 3.56 0 0 1.78 1.78 0 1.78 1.78 0 0 0 0

This appears to largely align with the timetable10 https://www.vline.com.au/getattachment/44615b59-182d-456a-a25d-57b25de3d88b/Yarram-Melbourne-(via-Leongatha-Koo-Wee-Rup) and meets expectations.

Melbourne CBD - North

Looking next Melbourne CBDm, SA1 and SA2 zone boundaries for the Melbourne CBD - North SA2 zone are shown below.

SA1 zone boundaries within the Melbourne CBD - North SA2, Source: ABS

SA1 zone boundaries within the Melbourne CBD - North SA2, Source: ABS

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for October 10, 2023, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for October 10, 2023, by hour between 5am and 1am

This appears to meet expectations, with peaks in the SI scores in morning and evening. SI scores also appear to be larger for zones closer to Melbourne Central station (south end of SA2 zone).

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for Saturday 14th October 2023, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for Saturday 14th October 2023, by hour between 5am and 1am

These results generally meet expectations. SI scores are in the order of half of the Tuesday scores, reflecting the lower service levels on Saturdays.

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for Sunday 15th October 2023, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for Sunday 15th October 2023, by hour between 5am and 1am

These results appear to meet expectations, with SI scores for the Sunday a relatively small amount lower than the Saturday scores

Clayton

The following shows calculated SI values for SA1 zones within the Clayton (North) - Notting Hill SA2 zone.

Victorian GTFS and SA1 zones within the Clayton (North) - NOtting Hill SA2 zone, SI values for October 10, 2023, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Clayton (North) - NOtting Hill SA2 zone, SI values for October 10, 2023, by hour between 5am and 1am

These results appear to largely match expectations. SI values are much lower than in the Melbourne CBD. The highest SI scores are generally in the SA1 zones that are closest to the bus interchange at Monash University (south-west area of the SA2 area).

Tram

Lang Lang

There are no trams in Lang Lang. Hence, extracting SI score results for SA1 21201154812 for just the trams results in no data:

Victorian GTFS and Lang Lang SA1 zone 21201154812, hourly SI values for October 10, 2023, 6am to 11pm only

area_id 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00 25:00

Melbourne CBD - North

Looking next at the Melbourne CBD:

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for October 10, 2023, tram only, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for October 10, 2023, tram only, by hour between 5am and 1am

Victorian GTFS and Melbourne CBD SA1 zone 20604150424 (RMIT and State Library), hourly SI values for October 10, 2023, 6am to 11pm only

area_id 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00 25:00
20604150424 350.08 347.55 334.63 307.59 304.8 307.34 311.83 333.62 368.9 371.78 335.5 255.37 196.24 160.72 144.61 145.27 65.22 2.54

This appears to meet expectations, with peaks in the SI scores in morning and evening. SI scores also appear to be larger for zones closer to the Swanston Street corridor

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for Saturday 14th October 2023, tram only, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for Saturday 14th October 2023, tram only, by hour between 5am and 1am

Victorian GTFS and Melbourne CBD SA1 zone 20604150424 (RMIT and State Library), hourly SI values for October 14, 2023, 6am to 11pm only

area_id 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00 25:00
20604150424 216.12 256.87 274.65 278.45 277.54 275.74 272.1 273.23 272.04 272.57 252.03 222.09 167.6 150.67 145.15 142.62 143.11 80.97

These results generally meet expectations. SI scores are in the order of 2/3rds of the Tuesday scores, reflecting the lower service levels on Saturdays.

Victorian GTFS and Melbourne CBD SA1 zone 20604150424 (RMIT and State Library), hourly SI values for October 15, 2023, 6am to 11pm only

area_id 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00 25:00
20604150424 126.14 161.27 240.57 275.31 277.33 278.68 271.31 273.23 271.61 272.57 237.87 158.09 118.63 106.99 107.3 106.89 25.13 0

These results appear to meet expectations, with SI scores for the Sunday a relatively small amount lower than the Saturday scores

Rail

Lang Lang

There are no rail services in Lang Lang. Hence, extracting SI score results for SA1 21201154812 for just the rails results in no data:

Victorian GTFS and Lang Lang SA1 zone 21201154812, hourly SI values for October 10, 2023, 6am to 11pm only

area_id 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00 25:00 26:00

Melbourne CBD - North

Looking next Melbourne CBD:

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for October 10, 2023, rail only, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for October 10, 2023, rail only, by hour between 5am and 1am

Victorian GTFS and Melbourne CBD SA1 zone 20604150424 (RMIT and State Library), hourly SI values for October 10, 2023, 6am to 11pm only

area_id 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00 25:00 26:00
20604150424 74.63 106.84 184.13 219.05 169.33 88.36 84.7 73.93 70.39 80.82 117.05 133.58 160.99 122.34 70.75 38.59 20.85 19.75 20.48 12.07 0 0

This appears to meet expectations, with peaks in the SI scores in morning and evening. SI scores also appear to be larger for zones closer to Melbourne Central and Flagstaff.

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for Saturday 14th October 2023, rail only, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for Saturday 14th October 2023, rail only, by hour between 5am and 1am

Victorian GTFS and Melbourne CBD SA1 zone 20604150424 (RMIT and State Library), hourly SI values for October 14, 2023, 6am to 11pm only

area_id 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00 25:00 26:00
20604150424 23.48 45.3 51.62 45.23 42.5 35.01 39.86 38.4 38.4 38.4 38.4 38.4 38.4 38.4 33.65 22.94 21.21 21.21 21.21 11.24 0 0

These results generally meet expectations. SI scores are in the order of half of the Tuesday scores, reflecting the lower service levels on Saturdays.

Victorian GTFS and Melbourne CBD SA1 zone 20604150424 (RMIT and State Library), hourly SI values for October 15, 2023, 6am to 11pm only

area_id 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00 25:00 26:00
20604150424 17.46 30.82 39.86 38.4 38.4 38.4 38.4 38.4 38.4 38.4 33.65 22.94 21.21 21.21 21.21 11.97 0 0

These results appear to meet expectations, with SI scores for the Sunday similar to the Saturday scores

Bus

Lang Lang

Extracting SI score results for SA1 21201154812 for just the buss results in:

Victorian GTFS and Lang Lang SA1 zone 21201154812, hourly SI values for October 10, 2023, 6am to 11pm only

area_id 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00
21201154812 1.78 3.56 1.78 0 1.78 1.78 1.78 1.78 1.78 1.78 1.78 1.78 1.78 1.78 1.78 0 1.78 0

This matches the pattern that was found when testing the gtfssupplyindex package, with a small amount of service throughout the day.

Melbourne CBD - North

Looking next Melbourne CBD:

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for October 10, 2023, bus only, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for October 10, 2023, bus only, by hour between 5am and 1am

Victorian GTFS and Melbourne CBD SA1 zone 20604150424 (RMIT and State Library), hourly SI values for October 10, 2023, 6am to 11pm only

area_id 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00
20604150424 69.2 133.18 175.48 146.59 108.71 99.99 97.29 101.74 105.34 107.36 135.24 154.27 126.14 90.65 78.28 63.21 44.62 43.57

This appears to meet expectations, with peaks in the SI scores in morning and evening. SI scores also appear to be larger for zones closer to the Queen and Lonsdale Street corridors

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for Saturday 14th October 2023, bus only, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for Saturday 14th October 2023, bus only, by hour between 5am and 1am

Victorian GTFS and Melbourne CBD SA1 zone 20604150424 (RMIT and State Library), hourly SI values for October 14, 2023, 6am to 11pm only

area_id 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00
20604150424 46.53 56.62 55.32 63.93 67.56 65.35 65.51 67.8 69.54 69.81 68.81 67.91 65.94 57.54 51.83 48.37 43.16 41.74

These results generally meet expectations. SI scores are in the order of half of the Tuesday scores, reflecting the lower service levels on Saturdays.

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for Sunday 15th October 2023, bus only, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Melbourne CBD - North SA2 zone, SI values for Sunday 15th October 2023, bus only, by hour between 5am and 1am

Victorian GTFS and Melbourne CBD SA1 zone 20604150424 (RMIT and State Library), hourly SI values for October 15, 2023, 6am to 11pm only

area_id 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00
20604150424 0 0.52 1.04 1.04 1.57 1.57 1.56 1.57 1.58 1.57 1.57 1.57 1.04 0.52 1.04 0.52 0.52 0

These results DO NOT meet expectations. The scores are much lower, being less than 5 percent of the Saturday scores. Is this an error in the calculations?

Sunday bus services in the CBD are generally much less frequent than any other time in the week, but this appears to be too much of a difference.

There were some strike actions by bus drivers around this time, which might account for dramatic reductions in the timetabled services. Also, there have been shortages of bus drivers, and if timetabled services need to be cut it would appear likely that the Sunday services would be the first to be dropped. However, these results still surprise me, so it will be worth investigating further by looking at Clayton.

Clayton

The following shows calculated SI values for SA1 zones within the Clayton (North) - Notting Hill SA2 zone.

Victorian GTFS and SA1 zones within the Clayton (North) - NOtting Hill SA2 zone, SI values for October 10, 2023, bus only, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Clayton (North) - NOtting Hill SA2 zone, SI values for October 10, 2023, bus only, by hour between 5am and 1am

These results appear to largely match expectations. SI values are much lower than in the Melbourne CBD. The highest SI scores are generally in the SA1 zones that are closest to the bus interchange at Monash University (south-west area of the SA2 area).

Victorian GTFS and SA1 zones within the Clayton (North) - NOtting Hill SA2 zone, SI values for October 14, 2023, bus only, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Clayton (North) - NOtting Hill SA2 zone, SI values for October 14, 2023, bus only, by hour between 5am and 1am

The Saturday scores meet expectations, being in the order of half those of Tuesday and following a similar geographic pattern.

Victorian GTFS and SA1 zones within the Clayton (North) - NOtting Hill SA2 zone, SI values for October 15, 2023, bus only, by hour between 5am and 1am

Victorian GTFS and SA1 zones within the Clayton (North) - NOtting Hill SA2 zone, SI values for October 15, 2023, bus only, by hour between 5am and 1am

Here the Sunday scores appear to make more sense than they did in the CBD. Scores are slightly lower than for Saturday, which is consistent with expectations.

CBD bus, different day

As discussed above, perhaps there was something strange going on in the timetable on Sunday October 15 - maybe associated with strike action or driver shortages. This suggests that reviewing the bus scores for another Sunday might be appropriate.

might be examined.

Discussion and conclusions

SI scores have been calculated for each hour on Tuesday 10th, Saturday 14th and Sunday 15th of October, 2023, for all SA1 2021 zones within Greater Melbourne. These calculations have been done using the new gtfssupplyindex R package, and results generally appear to meet expectations. More detailed testing of the code and hand calculation to check results has been reported in the documentation for the package on github (Reynolds 2024Reynolds, James. 2024. “Gtfssupplyindex.” https://github.com/James-Reynolds/gtfssupplyindex.), although there is further work to be done there.

Calculation speed is much improved from previous efforts (in mid-2023)! The three days of calculations ran overnight, and were completed in the morning.

Next steps might involve further development of the gtfssupplyindex package. Further exploration of the SA1 scores for Greater Melbourne that have been calculated here might also be undertaken, or further dates

References